The Kenyan government has dismissed a report by a Swiss research institute that says it is secretly helping Southern Sudan stockpile weapons in violation of a U.S.-backed peace agreement. The Small Arms Survey says Southern Sudan government forces have received tanks and weapons that had previously been held in Kenya.

In an interview with VOA, Kenya's Defense Ministry Spokesman Bogita Ongeri dismissed the Small Arms Survey report as speculation.

The document, which contains satellite images allegedly showing T-72 Soviet tanks at the Southern Sudan military headquarters, claims the vehicles were the same tanks that arrived in Kenya in 2008. The Swiss team that authored the report says the photos are credible proof the Kenyan government has helped South Sudan obtain weapons in violation of a peace deal backed by the United States.

But Ongeri told VOA there is no evidence to back the claims, and the tanks are still in the hands of the Kenyan military.

"We have clearly indicated that those are our tanks and they are. I do no know where they are getting those things," he said.

The Soviet tanks first arrived at the Kenyan port of Mombassa amid a blaze of publicity in 2008, aboard the MV Faina cargo ship. The Ukrainian-owned vessel had recently been released by pirates after it was hijacked off the coast of neighboring Somalia.

Media attention on the ship's military cargo had led to increasing speculation it had originally been headed for South Sudan. The Small Arms Survey says the tanks were part of three shipments secretly under contract to the Southern Sudan government that were delivered to Kenya's Ministry of Defense.

The tanks were taken to barracks outside Nairobi, where the government said they would be used by the Kenyan military. Since March last year, eyewitness reports and photographic evidence have placed the vehicles elsewhere.

In October last year, Kenyan police arrested the Seafarer's Assistance Program chief, Andrew Mwangura, after he claimed the MV Faina was originally destined for Southern Sudan.

The United States has warned that illicit weapons shipments are fueling insecurity and heightening tensions in South Sudan before a referendum that could result in the region's independence from Khartoum.

Kenya enjoys close military ties with the region, and between August and September last year the Kenyan army sent about 300 military experts to Juba to train soldiers who had once served as fighters in the guerrilla force, the SPLA.

Analysts are warning that north and south Sudan are entering into an arms race and are building up a heavy store of weapons.

Experts are worried the 2005 peace agreement could be under threat of breaking down. A lapse in the ceasefire would mean a return to a war that has already killed an estimated two-million Sudanese people.